Electrical switch



Aug. 15, 1950 c. A. WOODWARD ELECTRICAL SWITCH Filed March 29, 1949 INVENTOR:

CLEMENT A. WOODWARD BY 9% ATTORNEY.

Patented Aug. 15, 1950 ELECTRICAL SWITCH Clement A. Woodward, Wellesley, Mass., assignor to United-Carr Fastener Corporation, Cambridge, Mass., a corporation of Massachusetts Application March 29, 1949, Serial N0. 84,195

3 Claims.

1 This invention relates generally to electrical switches and has particular reference to a switch adapted to be enclosed in a housing and operated by a plunger extending from the housing.

Plunger operated electrical switches are fre-,

quently provided with a pair of Contact members mounted on a base in one end of the housing, and a shorting member disposed in the housing opposite the contact members for movement into and out of the contact position to make and break an electric circuit between the contacts. For convenience and economy in manufacture, the contact members are usually formed by providing a pair of hollow rivets in the base having lead Wires inserted therethrough from the back of the base, and secured thereto by solder applied to the rivets on the front of the base. With this construction, a small mound of solder is left on the end of the rivet, which serves as the contact surface to engage the shorting member.

Frequently, there will be considerable variation in height between such solder contact members, which may result in a poor connection when the shorting member is forced thereagainst. In some cases the difference in height between the members may be great enough to completely prevent completion of the circuit between the contacts by the shortin member.

The object of the invention is to provide a plunger operated switch in which a resiliently mounted shorting member is provided to complete an electric circuit between a pair of contact members.

A further object of the invention is to provide a plunger operated switch having a shorting member disposed to engage a pair of contact members, in which the shorting member is adapted for limited tilting movement to engagev contact members having a small but appreciable difference in height.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description, taken in conjunction with the accompanying drawing, in which:

Fig. l is a view in perspective of the component parts of the switch;

Fig. 2 is a view in elevation, partly in section of the assembled switch in the off position;

Fig. 3 is a view in elevation, partly in section, of the switch, in which the plunger is depressed sufficiently to engage one of the contact members;

Fig. 4 is a view in elevation, partly in section of the switch, in which the plunger has been sufii- 2 ciently depressed to cause the shorting member to tilt to engage both contact members; 1

Fig. 5 is a view in section taken on line 5- -5 of Fig. 2; and

Fig. 6 is a view in section taken on line 6-6 0 Fig.2. I

Referring to the drawing, there is illustrated-a plunger operated switch H], which is adapted to snap into engagement with a supporting panel I2. The switch It] comprises a pair of contact members I4 and I 6 mounted on a fixed base 18 in one end of a housing 20, and a shorting member 22 resiliently and movably mounted in an opening 24 in a movable base 26, which is slidable in the housing toward and away from the contacts'to cause" the shorting member to make and break an electric circuit therebetween. An operating plunger 28 extends from the housing 20 to provide means for forcing the base toward-the contacts, and an operating spring 30 is disposed between the movable base and the fixed base to bias the bases apart.

The contact members l4 and it each comprise a hollow eyelet 32 having a lead wire 34 inserted therein and soldered thereto at the inner end of the eyelet.' The soldering operation leaves a mound 36 ofsolder, which also serves asa contact surface to engage the shorting member.

The shorting member 22 is preferably in the form of a hollow eyelet having flanged ends 38 and 40. A spring 42 is provided between flanged end '38 and the base 25 to bias the shorting member into the extended position. The flanged end 40 serves to retain the shorting member 22 in assembly with the base. The diameter of the portion of the shorting member disposed through the opening 24 is sufiiciently smaller than the opening to allow substantial axial tilting of the shorting member for a purpose which will be hereinafter described.

During manufacture of the device, it frequently happens that one eyelet 32 will retain more solder than the other, which results in a difierence in height between the contact members. This effeet is illustrated in Figs. 2 to 4 in which the contact member 14 has a greater height than the contact member 16.

During operation of the switch, a force applied to the plunger 28 causes the base 26 to move in the housing, carrying the shorting member toward the contact members it and IS. The shorting member first engages the higher contact member M, as illustrated in Fig. 3. Further movement of the base 26 inwardly causes tilting of the shorting member and compression of the spring 42, to

allow the shorting member to contact the member 15 and thereby complete the circuit between the contact members.

The provision of a tiltable and resiliently mounted shorting member insures proper operation of the switch regardless of defects of the contact members in manufacture, and greatly reduces the number of switches rejected for such defects. The life of the switch is also prolonged since unequal wear of the contact members in service is compensated for by the tiltable shorting member.

Since certain obvious changes may be'm'ade in the device without departing from the scope of the invention, it is intended that all matter contained herein be interpreted in an illustrative, and not in a limiting sense.

I claim:

1. An electrical switch comprising: a housing; an operating plunger member disposed within the housing and having a portion extending out of one end of said housing, said plunger member having a. cavity opening on the end of said plunger member within said housing and a plate member disposed adjacent said end with an aperture opening on said cavity; spring means within said housing urging said inner end of said plunger member and said plate away from the opposite end of said housing; a shorting eyelet having a barrel loosely assembled within the aperture of said plate, a retaining flange at one end of said barrel disposed within the cavity of said plunger member, and a contact flange on the opposite end of saidbarrel spaced from said plate opposite said plunger member; a spring member surxrounding said barrel tending to urge said contact'flange away from said apertured plate; and

a pair of contacts mounted at the opposite end of said housing for engagement with said contact 'flange upon the application of external pressure tending to urge said plunger into said housing,

said eyelet and spring member providing means for compensating for minor difierences in height ;of the contact members.

2. An electrical switch comprising: 'atubular' disposed within said housing urging said inner end of said plunger member and said disc away from the opposite end of said housing; a shorting eyelet having a barrel loosely assembled within the aperture of said disc, a retaining flange at one end of said barrel disposed within the cavity of said plunger member, and a contact flange at the opposite end of said barrel spaced from said plate opposite said plunger member; a spring member surrounding said barrel tending to urge said contact flange away from said apertured disc; and an insulating disc mounted at the opposite end of said housing with a pair of contacts mounted thereon for engagement with said contact flange upon the application of external pressure tending to urge said plunger into said housing, said eyelet and said spring member providing means for compensating for minor differences in height of the contact members.

3.An'electrical switch comprising: a tubular housing; an insulating disc at one end with a pair of contact elements mounted thereon; an apertured cap member at the other end provided with snap fastener means for securing said cap member to said housing; an operating plunger member disposed within the housing and having a portion at one end extending through the aperture of said cap member, said plunger member having a cavity opening on the opposite end of said plunger member in said housing; an apertured disc member disposed adjacent said end with an aperture opening onsaid cavity; spring means within said cavity urging said inner end of said plunger member'and said disc away from the insulated mount of said contacts; a shorting eyelet having a barrel loosely assembled within the aperture of said disc, a retaining flange on one end of said eyelet disposed within the cavity of said plunger member, and a contact flange on the other end of said eyelet spaced from said disc opposite said plunger member; a helical spring member surrounding said barrel engaging said contact flange and said disc tending to urge said contact flange away from said disc, said eyelet and spring member providing means for compensating for minor differences in height of the contact members when by the application of external pressure to the portion of the plunger member extending through the cap member the contact flange of said eyelet is caused to engage said contact members.

CLEMENT A. WOODWARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,419,072 Hall Apr. 15, 1947 FOREIGN PATENTS Number Country Date 105,345 Switzerland Aug. 25, 1923 113,176 Great Britain Feb. 14, 1918 330,366 Germany Sept, 3, 1919 698,189 France Nov. 17, 1930 

